The present invention relates generally to the field of network interface devices, and more particularly to a communication bridge for interconnecting networks operating on different protocols, and able to perform logical functions on the data where desired.
Many different types of networks and network protocols have been developed and are presently in use. In industrial settings, for example, protocols are used to define the format for messages exchanged between devices, and to regulate traffic flow of the data. The protocol may define such parameters as the bits available for message data, the meaning of message data within the bits, as well as bits used for headers, trailing bits, and so forth. Specialized circuitry in each of the devices serves to encode and decode the data in accordance with the established protocol. In industrial and other environments, such protocols include control area network (CAN) protocols, device network (DeviceNet or DNet) protocols, Ethernet protocols, Internet protocols, and other specialized protocols, such as Profibus, Modbus, and so forth.
Depending upon the design of the particular device or component to be interfaced with a network, appropriate circuitry and programming may not always be present for communicating in accordance with the network protocol. In many instances, networks are divided into regions or segments, with different protocols being used within the different segments. For example, within a machine components may be designed to operate over one protocol, while the network to which the machine is connected operates in accordance with a different protocol. To accommodate such differences in hardware and programming, protocol or communication bridges have been developed that can store and translate data between the protocols. Such bridges are extremely useful in adapting standard components and machines to a variety of network protocols, allowing interfacing of many different components and machines or many different networks as desired.
While protocols bridges provide useful interfacing, heretofore known bridges of this type have not performed logical functions. That is, the bridges serve to facilitate the exchange of data between protocols, but are not equipped with logic circuitry that permits enhanced operation.
There is a need for improved bridging circuits that can enable certain logical operations. Such needs, however, have not been filled in the art or even recognized as such. Moreover, current designs for logic circuitry typically include logical programming circuitry in specialized control or monitoring systems, in specific components, and elsewhere. Communication bridging circuitry is considered completely separate and only added where necessary to existing logical circuits, always in separate devices with limited functionality.